Washing machine outlet boxes are commonly used in new housing construction or remodeling to provide the plumbing connections necessary for a washing machine. A washing machine outlet box typically includes at least three openings in the bottom wall of the box, one for connection of a drain pipe and the other two for mounting two water shut off valves inside the box for the hot and cold water supply lines.
The drain pipe and water shut off valves may be installed in several different arrangements depending on the particular plumbing layout and the type of washing machine outlet box used. For example, different types of washing machine outlet boxes can accommodate a right hand drain arrangement, a left hand drain arrangement, or a center drain arrangement.
For inventory considerations, it is generally known to provide a single washing machine outlet box that can accommodate all three drain arrangements so the plumber doesn't have to keep an inventory of different washing machine outlet boxes to accommodate these different drain arrangements. However, there is a continuing need to provide a washing machine outlet box that can more easily be adapted to accommodate any drain arrangement desired (i.e., either a right hand or left hand drain arrangement or a center drain arrangement). Also there is a continuing need to be able to quickly and easily seal the drain opening of any of the drain arrangements with a test cap when the washing machine outlet box is first installed for pressure testing of the sanitary drainage system to which the drain opening is connected for leaks, and once the pressure testing is completed, just as quickly and easily remove the test cap without risk of any portions of the test cap falling into the drain opening.